Attachment for straddle carrier



1952 0. F. CHRISTIANSEN 3,066,814

ATTACHMENT FOR STRADDLE CARRIER Filed Sept. 16, 1959 OVE F. CHRISTIANSEN ATTORNEY United rates li atenr 3,tl66,814 ATTAQHMENT FUR STRADDLE CARRIER Ove F. Christiansen, CopenhagemVanlose, Denmark, as-

Signor to Lars Arnhmr & Company, Copenhagen, Denmark Filed Sept. 16, 1959, Ser. No. 840,364 8 Claims. ill. 2l4392) This application relates an attachment for straddle carrier and the like, and more particularly to a lifting unit for the transportation of steel plates and the like.

Straddle carrier vehicles of known construction have gradually come to enjoy widespread application in the handling and transportation of long rod-shaped articles for example, wood trunks, pipes and the like. Various types of auxiliary equipment and attachments for straddle carriers have been utilized in the past to widen the field of application of the vehicle. The present invention relates to an attachment device in the form of a lifting unit which is especially suitable for the transportation of steel plates and the like.

It is known that by means of a conventional straddle carrier construction having the usual pivoted lifting hooks, that the vehicle can engage, lift and transport single or multiple plates which are chocked up on a support, but that it is especially difficult to enable the lifting hooks of the carrier to engage and remove one or more plates from the top of a stack of plates.

It is therefore an important object of the present invention to provide a lifting unit which is adapted to be associated with a straddle carrier and which is especially suitable for engaging and transporting one or more plates as aforesaid.

Another object is to provide a lifting unit of the type specified which reduces to a minimum the amount of space taken up by the attachment within the material handling space of the carrier structure.

A further object of the invention is to provide a device of the type contemplated which is capable of operating with maximum safety to personnel and equipment.

Still a further object of the invention is to generally improve the construction of attachment devices of the type contemplated.

These and other objects and advantages of the present invention, as will appear in the course of the description which follows below, are effected in the use of a vertically movable, longitudinally extending supporting frame having associated therewith a plurality of suspended lifting magnets; end portions of the magnet carrying supporting frame project substantially beyond both ends of the carrier and are provided with motor means, such as hydraulic cylinder and piston assemblies, for varying the efiective length of suspension members, such as cables, in order that the supporting frame may be raised and lowered as desired within the carrier body.

The arrangement of motor means on each opposite end portion of the magnet supporting frame aid-s in effecting the desirable result of maximizing the availability of space within the body of the straddle carrier; also, no interference with operator visibility results in the use of the preferred embodiment of the invention, and, at the same time, safe operation may be assured in the use of a motor design which limits to a predetermined maximum the load which can be transported by the carrier. Within the limitations of maximum safe loading, the lifting magnets can be designed to support readily a load of any given magnitude so that, together with the aforesaid motors, overloading of the carrier is avoided and a selected safety factor provided. Such construction is preferred to one wherein safety against overloading of the carrier is obtained by adjustment of the carrying capacity of the lifting ice magnets, in which case there is a risk that a load suspended from the magnets might be separated therefrom during transportation.

Suspension of the supporting frame on cables or equivalent means provides an advantage in that the frame is movable both longitudinally and transversely relative to the carrier when said frame is in a lowered position, whereby metal plates or other objects to be transported may be readily engaged even though the load lies in an inclined position relative to the carrier. When the straddle carrier is transporting such a load, it is, of course, desirable that the supporting frame be fixed in position relative to the carrier, which is readily accomplished in practice by locking the frame in relation to the carrier when the frame is in its upper position.

In a preferred embodiment of the lifting unit, the hydraulic cylinder motors are located lengthwise of the frame and each operates a suspension cable in a manner to be described. Preferably, the lifting unit has four independent hydraulic cylinder assemblies connected to a common pressure source, said cylinder assemblies being located side by side in pairs at each end of the supporting frame. Engine driven pumps which normally serve as a power source for operating the lifting books of the carrier may readily function as a common source for the hydraulic cylinder assemblies.

The lifting unit of the present invention is preferably adapted to be used in combination with the lifting hooks of straddle carriers, as aforesaid, wherein the supporting frame of the lifting unit is suspended from an attachment comprising an auxiliary straddle structure which is adapted to be carried by the lifting hooks of the carrier. Thus, the auxiliary straddle structure can be used with carriers of conventional design, and can, along with the lifting unit and associated structure, be readily mounted and dis mounted as desired, whereby to relieve the straddle carrier for other applications.

In the drawings:

FIGURE 1 shows a straddle carrier in side elevation and equipped with a lifting unit and auxiliary straddle structure, according to the invention; and

FIGURE 2 is a front elevational view of the construction shown in FIGURE 1.

The straddle carrier, as illustrated, is of conventional design and comprises two forward supporting legs 1 and two rear supporting legs 2, pairs of laterally spaced longitudinal frame members 3 and 4, and transverse tubular frame portions 5. Each of the carrier legs is associated .with a dirigible wheel 6, at least one pair of which are drive wheels. The superstructure of the carrier supports in a conventional manner a housing 7 which contains the engine and affords an operator station.

The straddle carrier further includes known lifting hooks 8 which extend along each side of the carrier and are suspended in the frame thereof so that they are adapted to be raised and lowered, as well as being swingable inwardly and outwardly. The lifting hooks 8 are, for the present purpose, assumed to be locked in the position shown in the drawing, and carry an auxiliary straddle structure which includes a plurality of pairs of upwardly extending side members or legs 9 and a transversely extending member 10 which forms a bridge structure. Members 9 are connected together at the lower ends thereof and longitudinally of the carrier structure by a pair of stringer members 9'. Cushioning blocks 11 preferably depend from transverse tubular members 5 for engagement with the bridge member If when the auxiliary structure is raised, as shown, whereby to firmly hold the auxiliary structure in position during movement of the carrier.

The auxiliary straddle structure 9, 9', 1% has mounted see ers at each of its upper four corner portions an anchor block 12 to which is secured a cable 13 which is adapted to serve as a hoisting and carrying cable for a supporting magnet frame 14. The length of the supporting frame 14 preferably 'is substantially greater than that of the straddle carrier, as shown. Each cable 13 is associated with a hydraulic cylinder 15 which is mounted lengthwise on the supporting frame 14 by a bracket 15 beyond the adjacent end of the straddle carrier and the auxiliary straddle structure 9, 1-0. A piston rod 16 of each cylin- .der carries at its free end a sheave 17 and the associated cable 13 forms a bight between a guide sheave 13 on the upper side of the supporting frame 14 and a fixed point 19 on the associated hydraulic cylinder 15.

In the position shown in the drawing, the four piston rods 16 are fully extended, under which condition the supporting frame 14 is raised fully. In this position the supporting frame 14 may engage stops, not shown, and so be located positively in relation to the auxiliary structure 9, 10, and also in relation to the straddle carrier. ,An inward movement of the piston rods 16 causes the supporting frame 14 to be lowered by increasing the effective cable length in a vertical direction, i.e., by increasing the length of the piece of cable extending from each of the anchor blocks 12 to the corresponding sheave 18.

The supporting frame 14 has a plurality of freely suspended lifting magnets 20, each of which are carried by three chains or cables 21, as shown, and are mounted such that the bottom surfaces of the various magnets are co-planar so as to facilitate the engagement and carrying of a plate member 2-2, for example.

It will be understood that the free height or space with- .in the straddle carrier bridge is maximized by a construction which provides hydraulic cylinders 15 located at the free ends of the supporting frame 14. Of course, the said cylinders need not be mounted longitudinally of the supporting frame, as shown, but could be readily located transversely, or, less desirably, in an upright position. in the latter arrangement some interference with operator visibility is to be expected, as well as possibly undesirably increasing the total height of the carrier.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A portable load handling device in combination with a straddle carrier having an inverted U-shaped frame and load hooks disposed within the frame for engaging material, comprising an upstanding auxiliary straddle structure adapted to be engaged by the load hooks for vertical movement within the frame of the straddle carrier, a load lifting unit suspended from the upper bridge portion of the auxiliary straddle structure and movable up and down relative thereto, said load lifting unit extending longitudinally substantially beyond either end of the auxiliary straddle structure, and motor means mounted upon the load lifting unit longitudinally beyond either end of the auxiliary straddle structure and operatively connected to the auxiliary straddle structure such that selective operation of the motor means effects lifting or lowering movement of the load lifting frame within the auxiliary straddle structure.

.2. A portable load handling device in combination with a straddle carrier having an inverted U-shaped frame and load hooks disposed within the frame for engaging material, comprising an upstanding auxiliary straddle structure adapted to be engaged by the load hooks for vertical movement within the frame of the straddle carrier, a load lifting unit suspended from the upper bridge portion of the auxiliary straddle structure and movable up and down relative thereto, said load liftingunit extending longitudinally substantially beyond either end of the auxiliary straddle structure, and motor means mounted upon the load lifting unit and operatively connected to the auxiliary straddle structure such that selective operation of the motor means effects lifting or lowering movement of the load lifting unit within the auxiliary straddle structure, said motor means including hydraulic cylinder and piston means extending in essentially parallel relation to th lifting unit and a flexible member operatively connected to the auxiliary straddle structure and to the lifting unit, extension of the hydraulic means effecting lifting movement of the load lifting unit.

3. A portable load handling device as claimed in claim 2 wherein sheave means is connected to the piston rod of the hydraulic means and to the load lifting unit, and anchor means associated With both the load lifting unit and with the auxiliary straddle structure, said flexible means extending between said anchor means and around said sheave means.

4. A portable load handling device in combination with a straddle carrier having load hooks operable within the bay of the carrier, comprising an inverted U-shaped auxiliary straddle structure adapted to be engaged and elevated by the load hooks of the straddle carrier, a load lifting unit suspended in a horizontal plane below the bridge portion of the auxiliary straddle structure and extending longitudinally beyond either end of the auxiliary straddle structure and of the straddle carrier, motor means mounted upon the load lifting frame longitudinally beyond either end of the auxiliary straddle structure and operatively connected to the auxiliary straddle structure for actuating the load lifting frame vertically within the auxiliary straddle structure, said auxiliary straddle structure being actuatable upwardly by the load hooks relative to the straddle carrier, and said lead lifting frame being actuatable upwardly relative to the auxiliary straddle structure.

5. A portable load handling device as claimed in claim 4 wherein the auxiliary straddle structure is actuatable upwardly into abutting engagement with stops located on the straddle carrier.

6. A lifting unit for transporting metal plates for use with a straddle carrier having an inverted U-shaped frame and load engaging means depending from the frame and disposed within the bay thereof, comprising an inverted U-shaped fixed frame engageable by the load engaging means for being transported by the straddle carrier, a lifting frame suspended from the fixed frame and having lifting means suspended therebeneath, said lifting frame being of a length substantially greater than that of the fixed frame, cylinder and piston actuator assemblies mounted upon the lifting frame, cable and sheave means operatively connected to the actuator assemblies, the lifting frame and the fixed frame in such a manner that extension and retraction of the actuator assemblies effects vertical movement of the lifting frame and actuator assemblies relative to the fixed frame, each cable means being anchored at one end relative to the lifting frame and at the opposite end relative to the fixed frame.

7. In combination, a straddle carrier having load hooks disposed within the bay thereof, a longitudinally extending framework supported on said load hooks for movement in a horizontal plane, a lifting frame suspended beneath the framework, lifting means depending from the lifting frame, said lifting frame extending substantially longitudinally beyond the opposite ends of the framework, hydraulic cylinder and piston actuator means mounted upon the lifting frame at each end portion thereof beyond the opposite ends of the framework and extending in a substantially horizontal plane, anchor means supported from each opposite end portion of the framework, wheel means mounted upon the lifting frame and the piston rod of each actuator means, anchor means supported from the lifting frame at a location intermediate the first mentioned anchor means and the piston rod connected wheel means of each actuator means, and flexible means reeving each pair of wheel means and secured at its opposite ends to a pair of said first and second mentioned anchor means, extension of the piston rod portions of said actuator means effecting an elevating movement of the lifting frame beneath the framework.

8. In combination, a straddle carrier having load hooks disposed wtihin the bay thereof, a pair of transversely spaced and longitudinally extending stringer members supported on said load hooks, upstanding support means connected to each stringer member, frame means connecting the upper ends of the upstanding support means, a lifting unit extending longitudinally of and below the frame means, said lifting unit extending a substantial distance beyond each end of the frame means, a plurality of lifting elements depending from the lifting unit, motor means mounted upon each end portion of the lifting unit beyond each end of the frame means, said motor means being operatively connected to the lifting unit and to the frame means for actuating the lifting unit in a vertical direction Within the frame means, said motor means including a plurality of fluid actuated cylinder assemblies mounted upon said opposite end portions of the lifting unit for vertical movement therewith and flexible support means operatively connected to the frame means, the lifting unit and each cylinder assembly.

References Cited in the file of this patent UNITED STATES PATENTS 2,583,075 Anderson et a1 Ian. 22, 1952 2,622,750 Ehlers Dec. 23, 1952 2,702,606 Young Feb. 22, 1955 2,760,661 Wight et a1. Aug. 28, 1956 2,902,183 Dodge Sept. 1, 1959 2,913,132 Cluck et al. Nov. 17, 1959 2,941,675 Noble et al June 21, 1960 2,959,310 Meister Nov. 8, 1960 FOREIGN PATENTS 158,668 Sweden Apr. 16, 1957 

